Engineering Commons^™

Synthesis Of Vo2/Poly(Mma-Co-Dmemuabr) Antimicrobial/Thermochromic Dual-Functional Coating And Reactivity Ratios Study, Yixian Liu

Electronic Thesis and Dissertation Repository

Antimicrobial/thermochromic dual-functional coatings were successfully synthesized via UV-curing. The quaternary ammonium compound (QAC) N,N-dimethyl-N-{2-[(2-methylprop-2-enoyl)oxy]ethyl}undecane-1-aminium bromide (dMEMUABr) was synthesized and copolymerized with methyl methacrylate (MMA) for antimicrobial properties. Vanadium oxide (VO₂) nanoparticles were evenly dispersed within the coating, providing thermochromic properties. The dual-functional coating showed high luminous transmittance (T_lum(25°C) =36.1 %) and solar energy modulation ( T_sol=5.8 %). 90.3 % of bacteria reduction was observed against Escherichia coli within 24 h contact. To further understand the sequence distribution of the copolymer poly(MMA-co-dMEMUABr), the reactivity ratios of MMA and dMEMUABr monomer were studied and compared under thermal …

Development Of Novel Solid-State Electrolytes For Sodium Ion Batteries, Fei Sun

Electronic Thesis and Dissertation Repository

Sodium ion battery is considered as a potential candidate to replace lithium ion battery. To eliminate the need for containment of the liquid electrolyte, the solid-state electrolytes attract more attention. However, solid state electrolytes are still restricted to be applied for commercialization because of the inherent low ionic conductivity and the poor mechanical properties. Therefore, my Ph.D. research is focused on developing advanced solid-state electrolytes by improving ionic conductivity and disclosing mechanisms of the electrolytes.

Firstly, a series of La substituted NASICON electrolytes are prepared to achieve high ionic conductivity of mS/cm, and the effects of La substitution concentration are …

Design Of Cell-Instructive Biomaterial Scaffolds For Intervertebral Disc Regeneration, Nadia Sharma

Electronic Thesis and Dissertation Repository

Biomaterials-based therapies targeting the nucleus pulposus (NP) have the potential to promote regeneration and restore mechanical function to the intervertebral disc. This study developed composite hydrogels incorporating decellularized NP (DNP) and assessed its effects on viability, retention and differentiation of U-CH1 cells, an NP progenitor-like cell line. A minimal protocol was developed to decellularize bovine NP that reduced nuclear content while preserving key extracellular matrix components predicted to be favourable for bioactivity. The resulting DNP demonstrated cell-instructive effects, supporting U-CH1 viability and retention within the hydrogels, and promoted the differentiation of the progenitor-like cells towards an NP-like phenotype. These studies …

Development Of Cellulose Nanofiber Reinforced Poly(Methyl Methacrylate), Tyler Bennett

Electronic Thesis and Dissertation Repository

Cellulose nanofiber (CNF), derived from renewable resources, is a good candidate to reinforce transparent plastics without sacrificing their transparency, owing to its size on the nano-meter scale, reflective index similar to the plastics’, excellent mechanical property, and low density. This study investigates effects of CNF on optical, viscoelastic, and thermal properties of CNF reinforced poly(methyl methacrylate) (PMMA). CNF/PMMA with different CNF contents and different types of PMMA were prepared through a solvent casting method with a low toxic and inexpensive solvent, acetone, and compression-molded to create nanocomposite films. The films were characterized using a transmission electron microscope, ultraviolet–visible (UV-Vis) spectrophotometry, …

Effect Of The Nonlinear Material Viscosity On The Performance Of Dielectric Elastomer Transducers, Yuanping Li

Electronic Thesis and Dissertation Repository

As a typical type of soft electroactive materials, dielectric elastomers (DEs) are capable of producing large voltage-induced deformation, which makes them desirable materials for a variety of applications in transduction technology, including tunable oscillators, resonators, biomimetics and energy harvesters. The dynamic and energy harvesting performance of such DE-based devices is strongly affected not only by multiple failure modes such as electrical breakdown, electromechanical instability, loss-of-tension and fatigue, but also by their material viscoelasticity. Moreover, as suggested by experiments and theoretical studies, DEs possess nonlinear relaxation processes, which makes modeling of the performance of DE-based devices more challenging.

In this thesis, …

Fabrication And Characterization Of Collagen-Polypyrrole Constructs Using Direct-Ink Write Additive Manufacturing, Rooshan Arshad

Electronic Thesis and Dissertation Repository

Current efforts in the tissue engineering field are being directed towards the creation of platforms which will facilitate in instructing cells towards biologically relevant outcomes such as stem cell differentiation and disease pathophysiology. Traditional fabrication methods serve as a limiting factor for the production of such platforms as they lack feature and geometric complexity. Additive Manufacturing (AM) offers advantage over said methods by affording designers creative freedom and great control over printed constructs. Such constructs can then be used to create appropriate models for study- ing a plethora of tissues and structures. An AM methodology for Direct-Ink Write (DIW) printing …

Additive Manufacturing Of Piezoelectric Photopolymer Ferroelectrets, Rami Abu Shammeh

Electronic Thesis and Dissertation Repository

Electroactive polymers are an emerging branch of smart materials that possess the capability to change shape in the presence of an electric field. Particularly, ferroelectrets are films of electrostatically charged dielectric polymer foam that comprise a growing portion of EAP literature. Ferroelectrets are characterized by a piezoelectric response and a quasi-permanent charge polarization owing to the dipoles created when the air cavities in the polymer matrix undergo dielectric breakdown. However, these cavities are often irregular in shape, size, and distribution when produced with conventional preparation methods. To overcome this, we employ a light-based additive manufacturing technique to create a hybrid …